Information About Classification

Classification is the separation of packets into traffic classes. You configure the device to take specific action on the specified classified traffic, such as policing or marking down, or other actions.

You can create class maps to represent each traffic class by matching packet characteristics with the classification criteria in Table 3-1.

Table 3-1 Classification Criteria

Classification Criteria

Description

CoS

Class of Service (CoS) field in the IEEE 802.1Q header.

IP precedence

Precedence value within the Type of Service (TOS) byte of the IP header.

Differentiated Services Code Point (DSCP)

DSCP value within the DIffServ field of the IP header.

QoS group

Locally significant QoS values that can be manipulated and matched within the system. The range is from 0 to 126.

Discard class

Locally significant values that can be matched and manipulated within the system. The range is from 0 to 63.

You can specify multiple match criteria, you can choose to not match on a particular criterion, or you can determine traffic class by matching any or all criteria.

Note However, if you match on an ACL, no other match criteria, except packet length, can be specified in a match-all class. In a match-any class, you can match on ACLs and any other match criteria.

Some match criteria relate only to ingress or egress traffic. For example, the internal label QoS group has no meaning on ingress traffic because it has not yet been assigned a value.

Traffic that fails to match any class in a QoS policy map is assigned to a default class of traffic called class-default. The class class-default can be referenced in a QoS policy map to select this unmatched traffic.

Note When you configure match all for a QoS class map by entering the class-map type qos match-all command, the match-all option does not work. Instead, the match criteria is always treated as match any.

You can reuse class maps within the same VDC when defining the QoS policies for different interfaces that process the same types of traffic.

Licensing Requirements for Classification

The following table shows the licensing requirements for this feature:

Product

License Requirement

NX-OS

QoS requires no license. Any feature not included in a license package is bundled with the Cisco NX-OS system images and is provided at no extra charge to you. For a complete explanation of the NX-OS licensing scheme, see the Cisco Nexus 7000 Series NX-OS Licensing Guide, Release 4.2.

Prerequisites for Classification

•You are in the correct virtual device context (VDC). A VDC is a logical representation of a set of system resources. You can use the switchto vdc command with a VDC number.

Guidelines and Limitations

Classification has the following guidelines and limitations:

•You can specify a maximum of 1024 match criteria in a class map.

•You can configure a maximum of 4096 classes for use in a single policy map.

•When you match on an ACL, the only other match you can specify is the Layer 3 packet length in a match-all class.

•You can classify traffic on Layer 2 ports based on either the port policy or VLAN policy of the incoming packet, but not both. Either the port policy or the VLAN policy takes effect, but not both; if both are present, the device acts on the port policy and ignores the VLAN policy.

Configuring ACL Classification

Note The device does not support the not form of this command.

You can classify traffic by matching packets based on existing ACLs. The permit and deny ACL keywords are ignored in the matching. QoS does not use the permit-deny functions of ACLs. You can classify by either IPv4 or IPv6.

Note Tunneled IP packets will not be matched unless the tunneling protocol is also IP, and then the match applies to the outer IP header and not the encapsulated IP header.

SUMMARY STEPS

1. config t

2. class-map [type qos] [match-any | match-all]class-map-name

3. match access-groupname acl-name

DETAILED STEPS

Command

Purpose

Step 1

config t

Example:

switch# config t

switch(config)#

Enters configuration mode.

Step 2

class-map [type qos] [match-any | match-all] class-map-name

Example:

switch(config)# class-map class_acl

Creates or accesses the class map named class-map-name, and then enters class-map mode. Class map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.

Step 3

match access-group name acl-name

Example:

switch(config-cmap-qos)# match access-group name my_acl

Configures traffic class by matching packets based on acl-name. The permit and deny ACL keywords are ignored in the matching.

Note The device does not support the not form of this command.

Use the show class-map command to display the ACL class map configuration:

switch# show class-map class_acl

Configuring DSCP Classification

You can classify traffic based on the DSCP value in the DiffServ field of the IP header. The standard DSCP values are found in Table 3-2.

Table 3-2 Standard DSCP Values

Value

List of DSCP Values

af11

AF11 dscp (001010)—decimal value 10

af12

AF12 dscp (001100)—decimal value 12

af13

AF13 dscp (001110)—decimal value 14

af21

AF21 dscp (010010)—decimal value 18

af22

AF22 dscp (010100)—decimal value 20

af23

AF23 dscp (010110)—decimal value 22

af31

AF31 dscp (011010)—decimal value 26

af32

AF40 dscp (011100)—decimal value 28

af33

AF33 dscp (011110)—decimal value 30

af41

AF41 dscp (100010)—decimal value 34

af42

AF42 dscp (100100)—decimal value 36

af43

AF43 dscp (100110)—decimal value 38

cs1

CS1 (precedence 1) dscp (001000)—decimal value 8

cs2

CS2 (precedence 2) dscp (010000)—decimal value 16

cs3

CS3 (precedence 3) dscp (011000)—decimal value 24

cs4

CS4 (precedence 4) dscp (100000)—decimal value 32

cs5

CS5 (precedence 5) dscp (101000)—decimal value 40

cs6

CS6 (precedence 6) dscp (110000)—decimal value 48

cs7

CS7 (precedence 7) dscp (111000)—decimal value 56

default

Default dscp (000000)—decimal value 0

ef

EF dscp (101110)—decimal value 46

Note Tunneled IP packets will not be matched unless the tunneling protocol is also IP, and then the match applies to the outer IP header and not the encapsulated IP header.

SUMMARY STEPS

1. config t

2. class-map [type qos] [match-any | match-all]class-map-name

3. match [not] dscpdscp-list

4. exit

5. copy running-config startup-config

`DETAILED STEPS

Command

Purpose

Step 1

config t

Example:

switch# config t

switch(config)#

Enters configuration mode.

Step 2

class-map [type qos] [match-any | match-all] class-map-name

Example:

switch(config)# class-map class_dscp

Creates or accesses the class map named class-map-name, and then enters class-map mode. The class-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.

Step 3

match [not] dscp dscp-list

Example:

switch(config-cmap-qos)# match dscp af21, af32

Configures the traffic class by matching packets based on dscp-values. The standard DSCP values are shown in Table 3-2.

Use the not keyword to match on values that do not match the specified range.

Step 4

exit

Example:

switch(config-cmap-qos)# exit

switch(config)#

Exits class-map queuing mode, and enters configuration mode.

Step 5

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

(Optional) Saves the running configuration to the startup configuration.

Use the show class-map command to display the DSCP class-map configuration:

switch# show class-map class_dscp

Configuring IP Precedence Classification

You can classify traffic based on the precedence value in the Type of Service (TOS) byte field of the IP header. Table 3-3 shows the precedence values.

Table 3-3 Precedence Values

Value

List of Precedence Values

<0-7>

IP precedence value

critical

Critical precedence (5)

flash

Flash precedence (3)

flash-override

Flash override precedence (4)

immediate

Immediate precedence (2)

internet

Internetwork control precedence (6)

network

Network control precedence (7)

priority

Priority precedence (1)

routine

Routine precedence (0)

Note Tunneled IP packets will not be matched unless the tunneling protocol is also IP, and then the match applies to the outer IP header and not the encapsulated IP header.

SUMMARY STEPS

1. config t

2. class-map [type qos] [match-any | match-all] class-map-name

3. match [not] precedenceprecedence-values

4. exit

5. copy running-config startup-config

`DETAILED STEPS

Command

Purpose

Step 1

config t

Example:

switch# config t

switch(config)#

Enters configuration mode.

Step 2

class-map [type qos] [match-any | match-all] class-map-name

Example:

switch(config)# class-map class_ip_precedence

Creates or accesses the class map named class-map-name, and then enters class-map mode. The class-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.

Step 3

match [not] precedence precedence-values

Example:

switch(config-cmap-qos)# match precedence 1-2, 5-7

Configures the traffic class by matching packets based on precedence-values. Values are shown in Table 3-3. Use the not keyword to match on values that do not match the specified range.

Step 4

exit

Example:

switch(config-cmap-qos)# exit

switch(config)#

Exits class-map queuing mode and enters configuration mode.

Step 5

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

(Optional) Saves the running configuration to the startup configuration.

Use the show class-map command to display the IP precedence class-map configuration:

Creates or accesses the class map named class-map-name, and then enters class-map mode. The class-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.

Configures the traffic class by matching packets based on the specified protocol. Use the not keyword to match on protocols that do not match the protocol specified.

Step 4

exit

Example:

switch(config-cmap-qos)# exit

switch(config)#

Exits class-map queuing mode and enters configuration mode.

Step 5

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

(Optional) Saves the running configuration to the startup configuration.

Use the show class-map command to display the protocol class-map configuration:

switch# show class-map class_protocol

Configuring QoS Group Classification

You can classify traffic based on the value of the QoS group internal label, which is not part of the packet payload or any packet header. You can set the value of the QoS group within a policy map using the set qos-group command as described in the "Configuring QoS Group Marking" section.

Note You match on the QoS group only in egress policies because its value is undefined until you set it in an ingress policy.

SUMMARY STEPS

1. config t

2. class-map [type qos] [match-any | match-all]class-map-name

3. match [not] qos-groupmulti-range-qos-group-values

4. exit

5. copy running-config startup-config

DETAILED STEPS

Command

Purpose

Step 1

config t

Example:

switch# config t

switch(config)#

Enters configuration mode.

Step 2

class-map [type qos] [match-any | match-all] class-map-name

Example:

switch(config)# class-map class_qos_group

Creates or accesses the class map named class-map-name, and then enters class-map mode. The class-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.

Step 3

match [not] qos-group multi-range-qos-group-values

Example:

switch(config-cmap-qos)# match qos-group 4, 80-90

Configures the traffic class by matching packets based on a list of QoS group values. Values can range from 0 to 126. The default QoS group value is 0. Use the not keyword to match on values that do not match the specified range.

Step 4

exit

Example:

switch(config-cmap-qos)# exit

switch(config)#

Exits class-map queuing mode and enters configuration mode.

Step 5

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

(Optional) Saves the running configuration to the startup configuration.

Use the show class-map command to display the QoS group class-map configuration:

switch# show class-map class_qos_group

Configuring Discard Class Classification

You can classify traffic based on the value of the discard class internal label, which is not part of the packet payload or any packet header. You can set the value of the discard class within a policy map using the set discard-class command as described in the "Configuring Discard Class Marking" section.

Note You match on the discard class only in egress policies because its value is undefined until you set it in an ingress policy.

SUMMARY STEPS

1. config t

2. class-map [type qos] [match-any | match-all]class-map-name

3. match [not] discard-classmulti-range-discard-class-values

4. exit

5. copy running-config startup-config

DETAILED STEPS

Command

Purpose

Step 1

config t

Example:

switch# config t

switch(config)#

Enters configuration mode.

Step 2

class-map [type qos] [match-any | match-all] class-map-name

Example:

switch(config)# class-map class_discard_class

Creates or accesses the class map named class-map-name, and then enters class-map mode. The class-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.

Step 3

match [not] discard-class multi-range-discard-class-values

Example:

switch(config-cmap-qos)# match discard-class 4, 60-62

Configures the traffic class by matching packets based on the list of discard-class values. Values can range from 0 to 63. The default discard class value is 0. Use the not keyword to match on values that do not match the specified range.

Step 4

exit

Example:

switch(config-cmap-qos)# exit

switch(config)#

Exits class-map queuing mode and enters configuration mode.

Step 5

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

(Optional) Saves the running configuration to the startup configuration.

Use the show class-map command to display the discard class class-map configuration:

switch# show class-map class_discard_class

Configuring Layer 3 Packet Length Classification

You can classify Layer 3 traffic based on various packet lengths.

Note This feature is designed for IP packets only.

SUMMARY STEPS

1. config t

2. class-map [type qos] [match-any | match-all]class-map-name

3. match [not] packet length min packet-length-list

4. exit

5. copy running-config startup-config

DETAILED STEPS

Command

Purpose

Step 1

config t

Example:

switch# config t

switch(config)#

Enters configuration mode.

Step 2

class-map [type qos] [match-any | match-all] class-map-name

Example:

switch(config)# class-map class_packet_length

Creates or accesses the class map named class-map-name, and then enters class-map mode. The class-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.

Step 3

match [not] packet length packet-length-list

Example:

switch(config-cmap-qos)# match packet length 2000

Configures the traffic class by matching packets based on various packet lengths. Values can range from 1 to 9198. Use the not keyword to match on values that do not match the specified range.

Step 4

exit

Example:

switch(config-cmap-qos)# exit

switch(config)#

Exits class-map queuing mode and enters configuration mode.

Step 5

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

(Optional) Saves the running configuration to the startup configuration.

Use the show class-map command to display the packet length class-map configuration:

switch# show class-map class_packet_length

Configuring CoS Classification

You can classify traffic based on Class of Service (CoS) in the IEEE 802.1Q header. This 3-bit field is defined in IEEE 802.1p to support QoS traffic classes. CoS is encoded in the high order 3 bits of the VLAN ID Tag field and is referred to as user_priority.

SUMMARY STEPS

1. config t

2. class-map [type qos] [match-any | match-all]class-map-name

3. match [not] coscos-list

4. exit

5. copy running-config startup-config

DETAILED STEPS

Command

Purpose

Step 1

config t

Example:

switch# config t

switch(config)#

Enters configuration mode.

Step 2

class-map [type qos] [match-any | match-all] class-map-name

Example:

switch(config)# class-map class_cos

Creates or accesses the class map named class-map-name, and then enters class-map mode. The class-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.

Step 3

match [not] cos cos-list

Example:

switch(config-cmap-qos)# match cos 4, 5-6

Configures the traffic class by matching packets based on list of CoS values. Values can range from 0 to 7. Use the not keyword to match on values that do not match the specified range.

Step 4

exit

Example:

switch(config-cmap-qos)# exit

switch(config)#

Exits class-map queuing mode and enters configuration mode.

Step 5

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

(Optional) Saves the running configuration to the startup configuration.

Use the show class-map command to display the CoS class-map configuration:

switch# show class-map class_cos

Configuring IP RTP Classification

IP Real-time Transport Protocol (RTP) is a transport protocol for real-time applications that transmits data such as audio or video and is defined by RFC 3550. Although RTP does not use a common TCP or UDP port, you typically configure RTP to use ports 16384 to 32767. UDP communications uses an even port and the next higher odd port is used for RTP Control Protocol (RTCP) communications.

You can configure classification based on UDP port ranges, which are likely to target applications using RTP.

SUMMARY STEPS

1. config t

2. class-map [type qos] [match-any | match-all]class-map-name

3. match [not] ip rtpudp-port-values

4. exit

5. copy running-config startup-config

DETAILED STEPS

Command

Purpose

Step 1

config t

Example:

switch# config t

switch(config)#

Enters configuration mode.

Step 2

class-map [type qos] [match-any | match-all] class-map-name

Example:

switch(config)# class-map class_rtp

Creates or accesses the class map named class-map-name, and then enters class-map mode. The class-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.

Step 3

match [not] ip rtp udp-port-value

Example:

switch(config-cmap-qos)# match ip rtp 2000-2100, 4000-4100

Configures the traffic class by matching packets based on range of lower and upper UDP port numbers, which is likely to target applications using RTP. Values can range from 2000 to 65535. Use the not keyword to match on values that do not match the specified range.

Step 4

exit

Example:

switch(config-cmap-qos)# exit

switch(config)#

Exits class-map queuing mode and enters configuration mode.

Step 5

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

(Optional) Saves the running configuration to the startup configuration.

Use the show class-map command to display the rtp class-map configuration:

switch# show class-map class_rtp

Configuring Class Map Classification

You can classify traffic based on the match criteria in another class map. You can reference the same class map in multiple policies.

Note•The referenced class map must be created prior to its reference.

•You can configure only one level of nesting of class maps. You cannot reference a class map that references another class map.

Use the following guidelines to configure class-map classification:

•To perform a logical OR with the class map specified in the match class-map command, use the match-any keyword. The match-any or match-all specification of the matched class map is ignored.

•To perform a logical AND with the class map specified in the match class-map command, use the match-all keyword. The match-any or match-all specification of the matched class map is ignored.

•Before you delete a referenced class map, you should delete all references to that class map.

SUMMARY STEPS

1. config t

2. class-map [type qos] [match-any | match-all]class-map-name

3. match [not] class-mapclass-map-name

4. exit

5. copy running-config startup-config

DETAILED STEPS

Command

Purpose

Step 1

config t

Example:

switch# config t

switch(config)#

Enters configuration mode.

Step 2

class-map [type qos] [match-any | match-all] class-map-name

Example:

switch(config)# class-map class_class_map

Creates or accesses the class map named class-map-name, and then enters class-map mode. The class-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.

Step 3

match [not] class-map class-map-name

Example:

switch(config-cmap-qos)# match class-map class_map3

Configures the traffic class by matching packets based on match criteria in another class map. Because match-all is the default for the class-map command, match criteria specified in class_map3 are ANDed with match criteria in class_class_map. Use the not keyword to match on values that do not match the specified range.

Step 4

exit

Example:

switch(config-cmap-qos)# exit

switch(config)#

Exits class-map queuing mode and enters configuration mode.

Step 5

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

(Optional) Saves the running configuration to the startup configuration.

Use the show class-map command to display the class-map class-map configuration:

switch# show class-map class_class_map

Verifying Classification Configuration

Use the show class-map command to verify the class-map configuration. This command displays all class maps.

switch# show class-map

...

Example Configuration

The following example shows how to configure classification for two classes of traffic: